Problem: Write a Lex Program to check valid Mobile Number.
Explanation:
FLEX (Fast Lexical Analyzer Generator) is a tool/computer program for generating lexical analyzers (scanners or lexers) written by Vern Paxson in C around 1987. Lex reads an input stream specifying the lexical analyzer and outputs source code implementing the lexer in the C programming language. The function yylex() is the main flex function which runs the Rule Section.
Examples:
Input: 7017175023 Output: Mobile Number Valid Input: 0001112223 Output: Mobile Number Invalid
Implementation:
/* Lex Program to check valid Mobile Number */ %{ /* Definition section */
%} /* Rule Section */ %% [1-9][0-9]{9} { printf ( "\nMobile Number Valid\n" );}
.+ { printf ( "\nMobile Number Invalid\n" );}
%% // driver code int main()
{ printf ( "\nEnter Mobile Number : " );
yylex();
printf ( "\n" );
return 0;
} |
Output:
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